Methylbenzene can undergo different reactions, as shown in Fig. 5.1. [Figure 5.1]

1. (a)(i)Draw structures in Fig. 5.1 for the possible organic products of the three reactions shown.[3]
2. (a)(ii)Complete Table 5.1. [Table 5.1][2]
3. (b)When methylbenzene reacts with an electrophile, a substitution reaction occurs. No addition reaction takes place under these conditions. Explain why no addition reaction takes place.[1]
4. (c)(i)The reaction of methylbenzene with thionyl bromide, SOBr2, in the presence of an iron(III) bromide catalyst, FeBr3, is shown in Fig. 5.2. [Figure 5.2] The mechanism of this reaction is similar to that of the bromination of benzene. The first step of the mechanism generates the SOBr⁺ electrophile, as shown. SOBr2 + FeBr3 → SOBr⁺ + FeBr4¯ The reaction of methylbenzene with SOBr+ ions is shown in Fig. 5.3. Complete the mechanism in Fig. 5.3. Include all relevant curly arrows and charges. Draw the structure of the organic intermediate. [Figure 5.3][3]
5. (c)(ii)The reaction shown in Fig. 5.2 produces a small amount of a by-product, P, with the molecular formula C14H14OS. Suggest a structure for by-product P.[1]
6. (d)(i)Acyl bromides, RCOBr, can be synthesised by the reaction of a carboxylic acid and SOBr2. This is a similar reaction to the synthesis of acyl chlorides using SOCl2. Give an equation for the reaction between ethanoic acid and SOBr2.[1]
7. (d)(ii)Suggest the relative ease of hydrolysis of acyl bromides, RCOBr, acyl chlorides, RCOCl, and alkyl chlorides, RCl. Explain your answer. easiest to hydrolyse hardest to hydrolyse[3]

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